68 BYZANTINE CHURCHES CHAP. acceptable to clergy from Western Europe, This,, however^ did not confer upon Roman priests an exclusive right to 'the use of the building, and the custom of allowing them to officiate there was often more conspicuous in the breach than in the observance. Still the Roman See always claimed the use of the church3 for in the letter addressed in 880 by Pope Julius VIII. to Basil I., that emperor is thanked for permitting Roman clergy to officiate again in SS.-Sergius and Bacchus according to ancient custom : c monasterium Sancti Sergii intra vestram regiam urbem constitutum3 quod sancta Romana Ecclesia j are proprio quondam retinuit, divina in-spiratione repleti pro honore Principis Apostolorum nostro praesulatui reddicfistis.'l The most distinguished hegoumenos of the monastery was John Hyiilas, better known5 on account of his learning, as the Grammarian3 and nicknamed Lecanomantis3 the Basin-Diviner5 because versed in the art of divination by means of a basin of polished brass. He belonged to a noble family of Armenian extraction, and became prominent during the reigns of Leo V., Michael II., and Theophilus as a determined iconoclast His enemies styled him Jannes, after one of the magicians who withstood Moses, to denote his character as a sorcerer and an opponent of the truth. Having occasion, when conducting service in the imperial chapel to read the lesson in which the prophet Isaiah taunts idolaters with the question, £ To whom then will ye liken God> or to what likeness will ye compare him ?' John, it is said, turned to Leo V., and whispered the significant comment, cHearest thou, my lord, the words of the prophet ? They give thee counsel/ He was a member of the Commission charged by that emperor to collect passages from the Holy Scriptures and the Fathers of the Church that condemned the use of images in worship. Prominent iconodules were interned in the monastery of Hormisdas in the hope that he would turn them from the error of their ways by his arguments and influence. He directed the education of Theophilus and supported the iconoclastic policy pursued by that pupil when upon the throne. 1 Epistola ccli. See Du. Cange, Const. Christ, iv. p. 116.